nounDate: circa 1900
a thorny Chinese tree (Poncirus trifoliata) of the rue family related to the citruses that has trifoliolate leaves and a sour yellow fruit resembling a small orange and that is grown for ornament or hedges or used as a rootstock for citrus fruits

trifoliate orange — /traɪˌfoʊliət ˈɒrɪndʒ/ (say truy.fohleeuht orinj) noun a small, thorny tree, Poncirus trifoliata, native to China, widely cultivated as an ornamental and for hedges and used as a stock for other citrus fruits. Also, trifoliata … Australian English dictionary

orange — /ˈɒrɪndʒ / (say orinj) noun 1. a globose reddish yellow edible citrus fruit of which there are two principal kinds, the bitter and sweet, the latter comprising the most important of the citrus fruits. 2. any of the white flowered evergreen… … Australian English dictionary